JPH0656154B2 - Electric blower - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electric blower used in a vacuum cleaner or the like.

2. Description of the Related Art A conventional electric blower of this type has a structure as shown in FIG. That is, the motor shaft 2 of the drive motor 1
A centrifugal impeller 3 is fixedly attached to the impeller 3, and an air guide 6 integrally formed with a diffuser 4 located around the impeller 3 and a return passage 5 following the diffuser 4 is provided adjacent to the impeller 3. The guide 6 and the casing 7 were covered. Then, the impeller 3 was rotated at a high speed to obtain the air volume and the vacuum pressure.

Problems to be Solved by the Invention However, the above-described conventional configuration has a problem that noise is large when operating the electric blower. That is,
The air flow discharged from between the blades of the impeller 3 flows into the diffuser 4 in a biased flow state such as a dense flow on the front side of the blades and a sparse flow on the rear side of the blades in the rotational direction. By colliding with the tip of the diffuser wall at the entrance of the diffuser 4, the compression wave is emphasized and can be heard as a large sound to the outside.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide an electric blower capable of reducing the noise by reducing the difference between sparse and dense dense waves in the discharge flow from an impeller. .

Means for Solving the Problems In order to solve the above problems, an electric blower according to the present invention includes a centrifugal impeller, an air guide integrally formed with a diffuser and a return passage, and an impeller and an air guide. The impeller includes a casing for covering and a motor for driving the impeller, and each blade of the impeller has a thickness that gradually increases from a central portion to an outer periphery, and an outer peripheral side from an intermediate portion branches into two branch portions. At least one of the front shroud and the rear shroud is configured to have a small hole at a position corresponding to a small space portion formed between the two branch portions of the blade and having an outer peripheral end open.

Action According to the above configuration, the flow that is unevenly distributed between the blades is
Since the blade becomes thicker toward the outer peripheral side, the sparse flow portion acts so as to be compensated by the blade, so that the inside of the impeller has a uniform flow. Further, the flow immediately after discharge from the impeller is a uniform flow between the blades and a flow that has passed through the small space portion flowing from the small holes of the shroud at the outer peripheral end of the small space portion, forming a uniform flow as a whole. Will be done. As a result, the flow has a reduced difference in density as a whole, the collision of compression waves at the tip of the diffuser wall is weakened, and an electric blower with a low noise level can be obtained.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

In the figure, reference numeral 11 is a casing, and an intake port 12 is formed in the center thereof, and the opposite side of the intake port 12 is attached to a motor frame 13 so as not to leak air. Centrifugal impeller 15 with multiple blades 14
Are attached to the motor shaft 16 by nuts 17.
An air guide 20 in which a diffuser 18 composed of a plurality of enlarged passages and a return passage 19 are integrated is installed on the outer periphery and below the impeller 15. Reference numeral 21 is a driving motor.

As shown in FIGS. 1 and 2, each blade 14 is composed of one blade on the impeller center side,
From the middle, it branches into two branch parts 14a, 14b to reach the outer circumference, and the outer circumference side is thicker than the center side, and the outer circumference is between the two branch parts 14a, 14b. A small space 22 having an open end is formed. A small hole 24 is formed at a position of the front shroud 23 corresponding to the position of the small space portion 22. 25 is a rear shroud.

Next, the operation will be described. The airflow inside the impeller 15 tends to be a dense flow on the front side in the rotational direction of the blade 14 and a sparse flow on the rear side as it goes from the center side to the outer peripheral side, but in the impeller 15 of the present embodiment, the blade is Since the thickness of 14 becomes thicker toward the outer circumference, the portion of the sparse flow is occupied by the blade 14. Therefore, the flow becomes uniform inside the impeller 15. Immediately after the discharge from the impeller 15, the small space 22
To the outer peripheral edge of the small hole 24 provided in the front shroud 23.
Since air is supplied from the outside of the impeller through the through hole, a uniform flow is formed around the outer circumference of the impeller. As a result, a uniform flow flows into the diffuser 18, the impact noise due to the difference in density is reduced, and an electric blower with a low noise level can be obtained. The small holes 24 may be formed in the rear shroud 25.

EFFECTS OF THE INVENTION As described above, according to the present invention, it is possible to reduce the difference in density between the inside of the impeller and the airflow after discharge, and it is possible to reduce the noise level.

[Brief description of drawings]

FIG. 1 is a partially cutaway plan view of an impeller of an electric blower according to an embodiment of the present invention, FIG. 2 is a sectional view of the same, FIG. 3 is a partially cutaway front view of the same electric blower, and FIG. It is a partially cutaway front view of an electric blower. 11 …… Casing, 14 …… Blade, 14a, 14b …… Branch, 15 …… Impeller, 18 …… Diffuser, 19 …… Return passage, 20 …… Air guide, 21 …… Motor, 22 …… Small space Part, 23 ... front shroud, 24 ... small hole, 25 ... rear shroud

Claims (1)

[Claims] 1. A centrifugal impeller, an air guide integrally formed with a diffuser and a return passage, a casing for covering the impeller and the air guide, and a motor for driving the impeller, each of the impellers being provided. The blade gradually becomes thicker from the center to the outer periphery,
Further, the outer peripheral side of the intermediate portion is branched into two branch portions, and at least one of the front shroud and the rear shroud of the impeller is a small space portion formed between the two branch portions of the blade and having an outer peripheral end open. Electric blower with small holes at corresponding positions.